Abstract

Spectrally resolved white-light phase-shifting interference microscopy has been used for measurements of the thickness profile of a transparent thin-film layer deposited upon a patterned structure exhibiting steps and discontinuities. We describe a simple technique, using an approach based on spectrally resolved optical coherence tomography, that makes it possible to obtain directly a thickness profile along a line by inverse Fourier transformation of the complex spectral interference function.

© 2010 Optical Society of America

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References

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  1. P. Hariharan and M. Roy, “Interferometric surface profiling with white light: effect of surface films,” J. Mod. Opt. 43, 1797–1800 (1996).
    [CrossRef]
  2. M. Roy, I. Cooper, P. Moore, C. J. R. Sheppard, and P. Hariharan, “White-light interference microscopy: effects of multiple reflections within a surface film,” Opt. Express 13, 164–170 (2005).
    [CrossRef] [PubMed]
  3. S. W. Kim and G. H. Kim, “Thickness profile measurement of transparent thin-film layers by white-light scanning interferometry,” Appl. Opt. 38, 5968–5973 (1999).
    [CrossRef]
  4. D. Kim, S. Kim, H. Kong, and Y. Lee, “Measurement of the thickness profile of a transparent thin film deposited upon a pattern structure with an acousto-optic tunable filter,” Opt. Lett. 27, 1893–1895 (2002).
    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]
  7. D. S. Mehta, H. Hinosugi, S. Saito, M. Takeda, T. Kurokawa, H. Takahashi, M. Ando, M. Shishido, and T. Yoshizawa, “Spectral interferometric microscope with tandem liquid-crystal Fabry–Perot interferometers for extension of the dynamic range in three-dimensional step-height measurement,” Appl. Opt. 42, 682–690 (2003).
    [CrossRef] [PubMed]
  8. D. S. Mehta, S. Saito, H. Hinosugi, M. Takeda, and T. Kurokawa, “Spectral interference Mirau microscope with an acousto-optic tunable filter for three-dimensional surface profilometry,” Appl. Opt. 42, 1296–1305 (2003).
    [CrossRef] [PubMed]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
  13. S. K. Debnath, M. P. Kothiyal, J. Schmit, and P. Hariharan, “Spectrally resolved white-light phase-shifting interference microscopy for thickness profile measurement of transparent thin-film layers on patterned substrates,” Opt. Express 14, 4662–4667 (2006).
    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]
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    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef]
  18. R. A. Leitgeb, M. Villiger, A. H. Bachmann, L. Steinmann, and T. Lasser, “Extended focus depth for Fourier domain optical coherence microscopy,” Opt. Lett. 31, 2450–2452 (2006).
    [CrossRef] [PubMed]
  19. A. Harasaki and J. C. Wyant, “Fringe modulation skewing effects in white-light vertical scanning interferometry,” Appl. Opt. 39, 2101–2106 (2000).
    [CrossRef]

2009

2007

Y.-S. Ghim and S.-W. Kim, “Fast, precise tomographic measurements of thin films,” Appl. Phys. Lett. 91, 091903 (2007).
[CrossRef]

2006

2005

2004

2003

2002

2001

S. S. Helen, M. P. Kothiyal, and R. S. Sirohi, “Analysis of spectrally resolved white light interferograms: use of a phase shifting technique,” Opt. Eng. 40, 1329–1336 (2001).
[CrossRef]

2000

1999

1996

P. Hariharan and M. Roy, “Interferometric surface profiling with white light: effect of surface films,” J. Mod. Opt. 43, 1797–1800 (1996).
[CrossRef]

J. Calatroni, A. L. Guerrero, C. Sainz, and R. Escalona, “Spectrally resolved white-light interferometry as a profilometry tool,” Opt. Laser Technol. 28, 485–489 (1996).
[CrossRef]

P. Sandoz, G. Tribillon, and H. Perrin, “High resolution profilometry by using phase calculation algorithms for spectroscopic analysis of white light interferograms,” J. Mod. Opt. 43, 701–708 (1996).
[CrossRef]

Ando, M.

Bachmann, A. H.

Calatroni, J.

J. Calatroni, A. L. Guerrero, C. Sainz, and R. Escalona, “Spectrally resolved white-light interferometry as a profilometry tool,” Opt. Laser Technol. 28, 485–489 (1996).
[CrossRef]

Cooper, I.

Debnath, S. K.

Escalona, R.

J. Calatroni, A. L. Guerrero, C. Sainz, and R. Escalona, “Spectrally resolved white-light interferometry as a profilometry tool,” Opt. Laser Technol. 28, 485–489 (1996).
[CrossRef]

Fercher, A. F.

Ghim, Y.-S.

Guerrero, A. L.

J. Calatroni, A. L. Guerrero, C. Sainz, and R. Escalona, “Spectrally resolved white-light interferometry as a profilometry tool,” Opt. Laser Technol. 28, 485–489 (1996).
[CrossRef]

Harasaki, A.

Hariharan, P.

Helen, S. S.

S. S. Helen, M. P. Kothiyal, and R. S. Sirohi, “Analysis of spectrally resolved white light interferograms: use of a phase shifting technique,” Opt. Eng. 40, 1329–1336 (2001).
[CrossRef]

Hinosugi, H.

Kim, D.

Kim, G. H.

Kim, S.

Kim, S. W.

Kim, S.-W.

Kong, H.

Kothiyal, M. P.

Kowalczyk, A.

Kurokawa, T.

Lasser, T.

Lee, Y.

Leitgeb, R.

Leitgeb, R. A.

Mehta, D. S.

Moore, P.

Perrin, H.

P. Sandoz, G. Tribillon, and H. Perrin, “High resolution profilometry by using phase calculation algorithms for spectroscopic analysis of white light interferograms,” J. Mod. Opt. 43, 701–708 (1996).
[CrossRef]

Roy, M.

Sainz, C.

J. Calatroni, A. L. Guerrero, C. Sainz, and R. Escalona, “Spectrally resolved white-light interferometry as a profilometry tool,” Opt. Laser Technol. 28, 485–489 (1996).
[CrossRef]

Saito, S.

Sandoz, P.

P. Sandoz, G. Tribillon, and H. Perrin, “High resolution profilometry by using phase calculation algorithms for spectroscopic analysis of white light interferograms,” J. Mod. Opt. 43, 701–708 (1996).
[CrossRef]

Schmit, J.

Sheppard, C. J. R.

Shishido, M.

Sirohi, R. S.

S. S. Helen, M. P. Kothiyal, and R. S. Sirohi, “Analysis of spectrally resolved white light interferograms: use of a phase shifting technique,” Opt. Eng. 40, 1329–1336 (2001).
[CrossRef]

Steinmann, L.

Sugai, M.

Takahashi, H.

Takeda, M.

Tribillon, G.

P. Sandoz, G. Tribillon, and H. Perrin, “High resolution profilometry by using phase calculation algorithms for spectroscopic analysis of white light interferograms,” J. Mod. Opt. 43, 701–708 (1996).
[CrossRef]

Villiger, M.

Wojtkowski, M.

Wyant, J. C.

Yoshizawa, T.

Appl. Opt.

S. W. Kim and G. H. Kim, “Thickness profile measurement of transparent thin-film layers by white-light scanning interferometry,” Appl. Opt. 38, 5968–5973 (1999).
[CrossRef]

A. Harasaki and J. C. Wyant, “Fringe modulation skewing effects in white-light vertical scanning interferometry,” Appl. Opt. 39, 2101–2106 (2000).
[CrossRef]

D. S. Mehta, M. Sugai, H. Hinosugi, S. Saito, M. Takeda, T. Kurokawa, H. Takahashi, M. Ando, M. Shishido, and T. Yoshizawa, “Simultaneous three-dimensional step-height measurement and high-resolution tomographic imaging with a spectral interferometric microscope,” Appl. Opt. 41, 3874–3885 (2002).
[CrossRef] [PubMed]

D. S. Mehta, H. Hinosugi, S. Saito, M. Takeda, T. Kurokawa, H. Takahashi, M. Ando, M. Shishido, and T. Yoshizawa, “Spectral interferometric microscope with tandem liquid-crystal Fabry–Perot interferometers for extension of the dynamic range in three-dimensional step-height measurement,” Appl. Opt. 42, 682–690 (2003).
[CrossRef] [PubMed]

D. S. Mehta, S. Saito, H. Hinosugi, M. Takeda, and T. Kurokawa, “Spectral interference Mirau microscope with an acousto-optic tunable filter for three-dimensional surface profilometry,” Appl. Opt. 42, 1296–1305 (2003).
[CrossRef] [PubMed]

S. K. Debnath, M. P. Kothiyal, J. Schmit, and P. Hariharan, “Spectrally resolved phase-shifting interferometry of transparent thin-films: sensitivity of thickness measurements,” Appl. Opt. 45, 8636–8640 (2006).
[CrossRef] [PubMed]

Y.-S. Ghim and S.-W. Kim, “Spectrally resolved white-light interferometry for 3D inspection of a thin film layer structure,” Appl. Opt. 48, 799–803 (2009).
[CrossRef] [PubMed]

Appl. Phys. Lett.

Y.-S. Ghim and S.-W. Kim, “Fast, precise tomographic measurements of thin films,” Appl. Phys. Lett. 91, 091903 (2007).
[CrossRef]

J. Mod. Opt.

P. Hariharan and M. Roy, “Interferometric surface profiling with white light: effect of surface films,” J. Mod. Opt. 43, 1797–1800 (1996).
[CrossRef]

P. Sandoz, G. Tribillon, and H. Perrin, “High resolution profilometry by using phase calculation algorithms for spectroscopic analysis of white light interferograms,” J. Mod. Opt. 43, 701–708 (1996).
[CrossRef]

Opt. Eng.

S. S. Helen, M. P. Kothiyal, and R. S. Sirohi, “Analysis of spectrally resolved white light interferograms: use of a phase shifting technique,” Opt. Eng. 40, 1329–1336 (2001).
[CrossRef]

S. K. Debnath and M. P. Kothiyal, “Optical profiler based on spectrally resolved white light interferometry,” Opt. Eng. 44, 013606 (2005).
[CrossRef]

Opt. Express

Opt. Laser Technol.

J. Calatroni, A. L. Guerrero, C. Sainz, and R. Escalona, “Spectrally resolved white-light interferometry as a profilometry tool,” Opt. Laser Technol. 28, 485–489 (1996).
[CrossRef]

Opt. Lett.

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Figures (9)

Fig. 1
Fig. 1

Simulated output data obtained with a rectangular spectral distribution for transparent films of SiO 2 ( n 2 = 1.46 ) deposited on a Si substrate, for film thicknesses (a) d = 5 μm , and (b) d = 2 μm . In these simulations, the top surface of the SiO 2 film, was assumed to be at a depth of z = 5 μm .

Fig. 2
Fig. 2

Values obtained for the thickness of the SiO 2 film as a function of the input thickness in simulations using a rectangular spectral distribution.

Fig. 3
Fig. 3

Gaussian spectral distribution used in these simulations.

Fig. 4
Fig. 4

Simulated output data obtained with a Gaussian spectral distribution for transparent films of SiO 2 ( n 2 = 1.46 ) deposited on an Si substrate, for film thicknesses (a) d = 5 μm and (b) d = 2 μm .

Fig. 5
Fig. 5

Values obtained for the thickness of the SiO 2 film as a function of the input thickness in simulations using a Gaussian spectral distribution.

Fig. 6
Fig. 6

Schematic of the spectrally resolved phase-shifting interference profilometer.

Fig. 7
Fig. 7

Profile along the z axis, at a single point on the slit, obtained with a silicon substrate coated with a SiO 2 film (nominal thickness 2 μm ).

Fig. 8
Fig. 8

Cross section of the test sample along the line defined by the slit.

Fig. 9
Fig. 9

Thickness variation of the SiO 2 film along the line defined by the slit.

Equations (7)

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G U U ( ν ) = G r r ( ν ) + n G n n ( ν ) + 2 Re { n m G n m ( ν ) exp [ 2 π i ν ( τ n τ m ) ] } + 2 Re { n G n r ( ν ) exp [ 2 π i ν ( τ n τ r ) ] } ,
F T { G U U ( ν ) } = Γ r r ( τ ) + n Γ n n ( τ ) + n m Γ [ τ + ( τ m τ n ) ] + n m Γ [ τ ( τ m τ n ) ] + n Γ [ τ + ( τ r τ n ) ] + n Γ [ τ ( τ r τ n ) ] ,
ψ ^ n r ( ν ) = n G n r ( ν ) exp [ 2 π i ν ( τ n τ r ) ] = Ψ ( ν ) exp [ i ϕ ( ν ) ] .
F T { ψ ( ν ) exp [ i ϕ ( ν ) ] } = n Γ [ τ ( τ r τ n ) ] .
ϕ = arctan ( I 1 5 I 2 + 11 I 3 + 15 I 4 15 I 5 11 I 6 + 5 I 7 + I 8 I 1 5 I 2 11 I 3 + 15 I 4 + 15 I 5 11 I 6 5 I 7 + I 8 ) = arctan N D ,
ψ = N 2 + D 2 4 .
F T { ψ ( ν ) exp [ i ϕ ( ν ) ] } = n Γ [ τ ( τ r τ n ) ] ,

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